<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
  <style media="screen">

    .btn {
      display: inline-block;
      width: 80px;
      padding: 6px 12px;
      font-size: 20px;
      text-align: center;
      border: 1px solid #ddd;
      cursor: pointer;
    }

    .btn span {
      position: relative;
      transition: .5s;
    }

    .btn span::after {
      content: '»';
      /*content: '\e183';*/
      position: absolute;
      top: 0;
      right: -15px;
      opacity: 0;
      transition: .5s;
    }

    .btn:hover span {
      padding-right: 15px;
    }


    .btn:hover span::after {
      opacity: 1;
      right: 0;
    }
  </style>
</head>
<body>
<div class="btn"><span>hover</span></div>
</body>
</html>
